Methods: This is a prospective, randomized and controlled study. From December 2010 to february 2011, 50 consecutive patients with palmar hyperhidrosis were treated with oxybutynin or placebo. Data were collected from 50 patients, and 5 (10,0%) patients were lost to follow-up. During the first week, patients received 2.5 mg of oxybutynin once a day in the evening. From the 8th to the 42nd day, they received 2.5 mg twice a day, and from the 43rd day to the end of the 12th week, they received 5 mg twice a day. All of the patients underwent 2 evaluations: before and after (12 weeks) the oxybutynin treatment, using a clinical questionnaire; and a clinical protocol for quality of life (QOL).